1. Field of the Invention
The present invention relates generally to communications networks, and more particularly to systems for generating transaction request messages and switching messages in transaction execution networks.
2. Description of the Related Art
Expanding communications capabilities has made possible the use of widely distributed networks for a large variety of applications. As but one example, networks have been provided to support communications in transaction processing systems that have users at locations remote from the transaction processing site. One transaction processing system that employs network architecture to support transaction processing is the Information Management System (IMS) available from IBM Corporation. The IMS product is a database management system (DBMS) that provides access to, and manages, a hierarchical database. In such networks, a transaction request can be entered into the system at one information management system (IMS) location, which processes the transaction and then sends the processed transaction back to the originating device or to one or more remote IMS locations for further processing.
The architecture of such networks typically provides for peer-to-peer communication, i.e., one IMS can communicate directly with another IMS for the purpose of transferring data. Under some circumstances, transaction requests and message switches can also be transmitted for remote execution of the request.
Remote processing of transaction requests is desirable. For example, remote transaction processing results in relatively greater flexibility in computational load sharing among the IMSs in the network. In other words, remote transaction processing facilitates distributing workload and distributing data storage requirements among the IMSs of the network.
Unfortunately, when a transaction request is entered from a program or device into the local IMS that is associated with that program or device, execution of the request by a remote IMS may not always be possible. This is because IMSs that are remote from the device may have input message buffer capacities which are not the same as the output buffer capacity of the local IMS. Consequently, a message having a prefix that is of the fixed specified length for processing in the local IMS will in many cases be incompatible for processing by remote IMSs. Also, when an IMS receives a message which contains fields that are not recognized by the IMS (which can happen when the message originates from an IMS having a higher software version than the receiving IMS), the receiving IMS will not retain the unrecognized fields, thereby causing corruption of the message.
Alternatively, all IMSs in the network can be retrofitted with software upgrades to have a common processing system (and, hence, to have buffers with compatible capacities). Unfortunately, retrofitting all IMS in a network is time-consuming and expensive, and typically must be repeated each time one IMS receives an improved processing program. Such repeated software upgrades would otherwise be necessary, without the present invention, to ensure compatibility, i.e., interoperability, of transaction processing for all IMSs.
As recognized by the present invention, remote transaction request and message switch processing can be established in a peer-to-peer system architecture without unduly expensive or time-consuming on-site refurbishment. Accordingly, it is an object of the present invention to provide a system and method for generating transaction request messages which can be processed in IMSs that are remote from the IMS into which the request is originally entered. Another object of the present invention is to provide a system and method for generating message switches which can be processed in IMSs that are remote from the IMS into which the message switch is originally entered. Still another object of the present invention is to provide a system and method for generating messages which is easy to use and cost-effective to manufacture. Another object of the present invention is to provide a system and method for generating messages which provides for adding new message features and modifying existing message features in networks without loss of data and without requiring changes to the software of the IMSs in the network.